The present invention generally relates to switching of the access path to a logical storage device in a storage system.
The technologies disclosed in Japanese Application Laid Open Nos. 2007-72571, 2005-202495, and 2004-227558, for example, are known as technologies relating to the switching of the access path to a logical storage device in a storage system.
According to Japanese Application Laid Open No. 2007-72571, an access path can be switched by changing both the multipath management software of the host and the storage path definition.
According to Japanese Application Laid Open No. 2005-202495, as a result of the migration destination storage system performing data migration from the migration source storage system after changing the host access destination port setting, migration with a host fault-tolerant system can be implemented.
According to Japanese Application Laid Open No. 2004-227558, a virtualization control device which is located between the host and the storage system is able to implement data migration and change the access destination device without changing the identification information with which the host identifies volumes.
According to Japanese Application Laid Open Nos. 2007-72571 and 2005-202495, the host is required to possess a function for changing the access path. The operation of changing the settings of the access path involves problems that differ for each OS (operating system) of the host.
According to Japanese Application Laid Open No. 2004-227558, there is no need for the host to possess a function for changing the access path. However, the virtualization control device is required to perform access path virtualization processing not only at the time of data migration but also during normal operation (when the host issues an access command to the storage system). Hence, in order to prevent a functional bottleneck, a high-performance virtualization processing circuit and processor must be installed.